Compression Test

[Greengooey]

I did a compression test yesterday on my 240z and it was this:

#1 - 180

#2 - 177

#3 - 180

#4 - 183

#5 - 180

#6 - 184

The #3 cylinder compression came up slowly (over 10 revolutions) compared to the other 5 cylinders. When the car is running I can pull the boot off the plug of cylinder #3 and there is no rpm change as there is with with the other 5 cylinders. The engine does not run smooth but it is not irratic either; the engine also runs well under acceleration. I am also getting a spark from the boot to the plug on cylinder #3.

Do I need to check the timing? I don't understand why the compression is good across the board but it seems like the plug in cylinder #3 isn't firing. Please list any suggestions you have.

Also the front 3 plugs (1,2, and 3) are almost fouled out from the front carb running rich.

[2ManyZs]

There's nothing wrong with those numbers... sounds to me like the first thing you ought to do is a complete tune up. Plugs, wires, cap, rotor, points etc, then check your timing. After you do this, drive it a bit and then see what the plugs look like. If they are still loading up on 1-3 and the rest look OK, you'll need to go to the carbs. No sense messing with the carbs till you rule out all the other possible problems that are cheaper and require less work to fix.

[Greengooey]

Will do, thanks.

[ZmeFly]

Is to also adjust your valves while your doing everything else. That way your sure to know that everything is in correct tune.